The invention relates to control apparatus for damping vibration impulses in preparation systems for stock suspensions, in particular fibrous suspensions. One such vibration damping control apparatus is known from "Das Papier", No. 10A, 1975, Pages V 144 to V 151.
Vibration impulses in pipe lines cause difficulties, particularly in the field of paper manufacture. The impulses originate far in front of the paper machine during the preparation of the pulp and the impulses travel right up to the head box of the paper machine, which results in irregular distribution of weight per unit area. Those machine parts which produce vibration impulses include pumps in particular, but also include so-called wire screens, in which a screening element, preferably in the form of a rotor having airfoils or blades, rotates generally in front of a rotationally symmetric wire basket. The individual screening elements particularly are the cause of such impulses. Therefore, the above-mentioned damping control apparatus for vibration damping was installed between such a screen disposed in front of the paper machine and the head box. One example of such apparatus is described in German Pat. No. 27 51 949.